Which of the following factors determine the actual O2 provided ...

[mynx]

Which of the following factors determine the actual O2 provided by an air-entrainment system? 1. O2 input flow to the jet 2. Air-to-O2 ratio of the device 3. Resistance downstream from the jet
 
  a. 2 and 3 only
  b. 1 and 2 only
  c. 1, 2, and 3
  d. 1 and 3 only

Question 2

A patient receiving 35 O2 through an air-entrainment mask set at 6 L/min input flow becomes tachypneic.
 
  Simultaneously, you notice that the SpO2 has fallen from 91 to 87. Which of the following actions would be most appropriate in this situation?
  a. Switch the patient to a 40 air-entrainment mask.
  b. Increase the device's input flow to 10 L/min.
  c. Switch the patient to a 28 air-entrainment mask.
  d. Decrease the device's input flow to 4 L/min.

[leannegxo]

Answer to Question 1

ANS: A
The FiO2 provided by air-entrainment devices depends on two key variables: the air-to-O2 ratio and the amount of flow resistance downstream from the mixing site.

Answer to Question 2

ANS: B
A patient is receiving O2 through an air-entrainment device set to deliver 50 O2. The input O2 flow is set to 15 L/min. What is the total output flow of this system?
SOLUTION
Step 1: Compute the air-to-O2 ratio by substituting 50 for the  O2
Step 2: Add the air-to-O2 ratio parts:
1. 7 + 1 = 2.7
Step 3: Multiply the sum of the ratio parts times the O2 input flow:
2. 7  15 L/min = 41 L/min
An air-entrainment device set to deliver 50 O2 that has an input flow of 15 L/min provides a total output flow of approximately 41 L/min.

[mynx]

Thanks for the timely response, appreciate it

[mohan]

Excellent